Method of making semisteel bearings, &amp; c.



No. 652,845. Patented July 3, I900. J. B. HALIFAX. MAKING SEMISTEELBEARINGS, &c. (Application filed Nov. 9, 1899.) (No Model.)

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\\IIIIIIIIIIIIIIIII fl UNITED STATES PATENT Fries. 7

JOHN B. HALIFAX, or CHICAGO, ILLINOIS.

METHOD OF MAKING SElVllSTEEL BEARINGS, 86C.

SPECIFICATION forming part of Letterslatent No. 652,845, dated July 3,1900.

Applicationrfilecl November 9, 1899. Serial No. 736 ,315. (No model.)

To all whom it may concern.-

Be it known that 1, JOHN B. HALIFAX, a citizen of the United States, anda resident of Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Methods of ProducingBearings and Analogous Articles from Semisteel, of which the followingis a specification.

This invention relates to an improved method of producing bearings andanalogous articles from semisteel; and the object of the invention is toproduce a cone or analogous wearing member of a bearing of superiorquality and at the same time at a minimum cost.

The invention consists in the matters hereinafter described, and moreparticularly pointed out in the appended claim, and will be readilyunderstood, reference being hadto the accompanying drawings, in whichFigure 1 is a plan View of a blank suitable for forming a bearing inaccordance with the present invention. Fig. 2 is a sectional view of thesame. Fig. 3 is a side elevation of a bicycle cone-bearing embodying theinvention. Fig. 4 is an axial sectional view of the same enlarged. Fig.5 is an axial sectional view of a pair of dies for forming the bearingshown in the preceding figures.

Bearing-cones have heretofore usually been made by either one or theother of two general methods, the method adopted depending upon thematerial employed, whether toolsteel capable of being tempered orBessemer orsemisteel adaptedforcase-hardening. The present inventionrelates to improvements in bearings of the latter type-'4'. 6., bearingsmade of semisteel and case-hardened.

The usual method of making a conefrom semisteel has been to turn it froma bar or rod of steel by means of a suitable lathe, next thread it, thencase-harden it, and finally grind its bearing-surface. A largeproportion of the cones made in this manner are seriously defective, thedefects being due, among others, to the following reasons: first, to thewarping, inequality, or contraction and distortion of the article duringcase-harden-- ing. This is undoubtedly more or less due to inequalitiesin the homogeneity of the metal, such as the grain of the metal, and toexisting internal strain, due to the rolling or drawing of the stock inmaking. The intense heat is more or less distortion of the article.subsequent grinding of the bearing if proparrangement of the molecules,and the result The erly done makes the cone-surface true, but

can obviously not correct any distortion of the threaded or seat portionof the cone, so that while the cone may have a perfect conesurface, yetit may nevertheless be and usually is more or less out of center whenseated. A second source of defects is due to the imperfections in thehardened skin formed by case-hardening in the form of flaws, which mayshow when the cone is first dressed or may only develop under wear.

These defects must obviously be due largely, 7

if not entirely, to lack of homogeneity of the metal.

' The present invention consists in making bearings as follows: First,cutting out the annular blanks of relatively-soft semisteel, such as issuitable for diework, having a cross-sectional form radically differentfrom that of the proposed bearing and also of somewhat greatercross-sectional area. Desirably for all ordinary forms of bearings theblanks will be rectangular in cross-section. Next, cold-pressing suchblanks between a suitable pair of. dies by means of gradually-appliedpressure (usually by use of a hydraulic press) and under sufficientpressure to cause the metal to flow into all the lines of the mold ordie and assumethe required cross-sectional form, while at the same timeit is greatly densified. This latter step of cold-flowing the metal intoform is not to be confused with ordinary die pressing and drawing. Inthe latter method the metal is worked into form by a series ofprogressive steps, during which the metal substantially preserves theintegrity of its character, such as its grain, density, &c. On thecontrary, in the carrying out of the present invention the metalpractically entirely changes its formation and becomes changed from ametal having a distinct grain to an amorphous homogenous body of. greatdensity,showing on fracture radically-distinct characteristics. Thebearings thus formed are next threaded (if intended to fita threadedseat) and next case-hardened in the usual manner, and it is this latterstep which brings out the distinctive characteristics of thecoldnecessary in case-hardening permits the reflowed cone. It is foundin practice that the distortion of such cones during case-hardening isvery slight, that the shrinkage is almost exactly uniform in differentcones of the 5 same size,and that the case-hardening is much moreperfect and free from flaws. All these results are attributable to theuniformity and density of the texture of the bearing before hardening.Upon breaking a cone made in this manner the unhardened interior isfound to be of a fine dense grainless texture, while the skin orhardened exterior extends inwardly to a practically-uniform depth allover the article, the juncture of the hardened and I5 unhardenedportions being shown in a sharply-defined line. The texture of thehardened portion also shows the increased density and uniformity. Afterhardening the wearing-surface is polished or, if very perfect accuracyis desired, the surface is ground in the usual manner.

Referring to the drawings, A designates a blank which may be struck outof sheet metal by means of a die or cut from tubular stock.

B designates an ordinary bicycle crankcone formed from the blank A, ashereinbefore described.

0 C designate two members of a pair of dies by means of which the conemay be made.

In practice the center or mandrelc of the die which occu pies theaperture of the blank during its formation into abearingis made movablewithin the main body of the die to facilitate disengagement of articleafter pressing, being in the present instance simplyprovided with ashank c, seated in the lower member and held against inward endwisemovement by a shoulder 0 It will of course be understood that thepresent invention is not limited to the production of the particularbearing shown; but, on the contrary, the method may be advantageouslyemployed in the production of any bearing or analogous semisteel articlewhich requires that it should have the peculiar characteristics producedby my improved method.

I do not claim herein the article produced by my improved method, thishaving been described and claimed in a. prior application filed by meMarch 6, 1899, Serial No. 707,897.

I claim as my invention-- The method of making bearings and analogousarticles of the general character described, which consists in forming ablank of semisteel larger in cross-sectional area than, and ofdistinctly-dilferent form from, that of the proposed article,cold-pressing said blank between dies to which pressure is appliedgradually and sufficient to condense the metal and at the same timecause it to How into the required form and finally case-hardening thearticle.

In testimony that I claim the foregoing as my invention I afiix mysignature hereto, in the presence of two subscribing witnesses, this 3dday of November, A. D. 1890.

JOHN B. HALIFAX.

Witnesses:

EDWARD 0. RICE, HENRY C. SCI-IUENEMA-N.

